This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Open AccessArticle
Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy
by
Tobias Guckeisen
Tobias Guckeisen
,
Rozalia Orghici
Rozalia Orghici † and
Silke Rathgeber
Silke Rathgeber *
Institute for Integrated Natural Sciences, Physics Department, University of Koblenz, Universitätsstraße 1, 56070 Koblenz, Germany
*
Author to whom correspondence should be addressed.
†
Current address: Institute for Applied Materials—Electrochemical Technologies, Karlsruhe Institute of Technology, Adenauerring 20b, 76131 Karlsruhe, Germany.
Polymers 2024, 16(15), 2170; https://doi.org/10.3390/polym16152170 (registering DOI)
Submission received: 19 June 2024
/
Revised: 22 July 2024
/
Accepted: 25 July 2024
/
Published: 30 July 2024
Abstract
Recent studies show that biofilm substances in contact with nanoplastics play an important role in the aggregation and sedimentation of nanoplastics. Consequences of these processes are changes in biofilm formation and stability and changes in the transport and fate of pollutants in the environment. Having a deeper understanding of the nanoplastics–biofilm interaction would help to evaluate the risks posed by uncontrolled nanoplastic pollution. These interactions are impacted by environmental changes due to climate change, such as, e.g., the acidification of surface waters. We apply fluorescence correlation spectroscopy (FCS) to investigate the pH-dependent aggregation tendency of non-functionalized polystyrene (PS) nanoparticles (NPs) due to intermolecular forces with model extracellular biofilm substances. Our biofilm model consists of bovine serum albumin (BSA), which serves as a representative for globular proteins, and the polysaccharide alginate, which is a main component in many biofilms, in solutions containing Na with an ionic strength being realistic for fresh-water conditions. Biomolecule concentrations ranging from 0.5 g/L up to at maximum 21 g/L are considered. We use non-functionalized PS NPs as representative for mostly negatively charged nanoplastics. BSA promotes NP aggregation through adsorption onto the NPs and BSA-mediated bridging. In BSA–alginate mixtures, the alginate hampers this interaction, most likely due to alginate–BSA complex formation. In most BSA–alginate mixtures as in alginate alone, NP aggregation is predominantly driven by weaker, pH-independent depletion forces. The stabilizing effect of alginate is only weakened at high BSA contents, when the electrostatic BSA–BSA attraction is not sufficiently screened by the alginate. This study clearly shows that it is crucial to consider correlative effects between multiple biofilm components to better understand the NP aggregation in the presence of complex biofilm substances. Single-component biofilm model systems based on comparing the total organic carbon (TOC) content of the extracellular biofilm substances, as usually considered, would have led to a misjudgment of the stability towards aggregation.
Share and Cite
MDPI and ACS Style
Guckeisen, T.; Orghici, R.; Rathgeber, S.
Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy. Polymers 2024, 16, 2170.
https://doi.org/10.3390/polym16152170
AMA Style
Guckeisen T, Orghici R, Rathgeber S.
Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy. Polymers. 2024; 16(15):2170.
https://doi.org/10.3390/polym16152170
Chicago/Turabian Style
Guckeisen, Tobias, Rozalia Orghici, and Silke Rathgeber.
2024. "Correlative Effects on Nanoplastic Aggregation in Model Extracellular Biofilm Substances Investigated with Fluorescence Correlation Spectroscopy" Polymers 16, no. 15: 2170.
https://doi.org/10.3390/polym16152170
Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details
here.
Article Metrics
Article metric data becomes available approximately 24 hours after publication online.